ACCESS(2)               COMMAND REFERENCE               ACCESS(2)



NAME
     access - determine accessibility of file

SYNOPSIS
     #include <sys/file.h>

     access(path, mode)
     char *path;
     int mode;

DESCRIPTION
     Access checks the given file path for accessibility
     according to mode.  Mode is the inclusive or of the
     following values, defined in <sys/file.h>:

          #define   R_OK 4    * test for read permission *
          #define   W_OK 2    * test for write permission *
          #define   X_OK 1    * test for execute (search) permission *
          #define   F_OK 0    * test for presence of file *

     Specifying mode as F_OK (i.e. 0) tests whether the
     directories leading to the file can be searched and the file
     exists.

     The real user ID and the group access list (including the
     real group ID) are used in verifying permission, so this
     call is useful to set-user-id programs.

     Notice that only access bits are checked.  A directory may
     be indicated as writable by access, but an attempt to open
     it for writing will fail (although files may be created
     there); a file may look executable, but execve will fail
     unless it is in proper format.

DIAGNOSTICS
     Access to the file is denied if one or more of the following
     are true:

     [ENOTDIR]      A component of the path prefix is not a
                    directory.

     [ENAMETOOLONG] The argument path is too long.

     [ENOENT]       The named file does not exist.

     [ENOASCII]     The argument path contains a byte with the
                    high-order bit set.

     [ELOOP]        Too many symbolic links were encountered in
                    translating the pathname.

     [EROFS]        Write access is requested for a file on a



Printed 4/6/89                                                  1

ACCESS(2)               COMMAND REFERENCE               ACCESS(2)



                    read-only file system.

     [ETXTBSY]      Write access is requested for a pure
                    procedure (shared text) file that is being
                    executed.

     [EACCES]       Permission bits of the file mode do not
                    permit the requested access; or search
                    permission is denied on a component of the
                    path prefix.  The owner of a file has
                    permission checked with respect to the
                    ``owner'' read, write, and execute mode bits,
                    members of the file's group other than the
                    owner have permission checked with respect to
                    the ``group'' mode bits, and all others have
                    permissions checked with respect to the
                    ``other'' mode bits.

     [EFAULT]       Path points outside the process's allocated
                    address space.

RETURN VALUE
     Upon successful completion, a value of 0 is returned.
     Otherwise, a value of -1 is returned and errno is set to
     indicate the error.

SEE ALSO
     chmod(2) and stat(2).



























Printed 4/6/89                                                  2

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di:2403,693;3456,964;
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se:4700,152;
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